Textile treatment compositions suitable for providing fabric softening and static control benefits during laundering are well-known in the art and have found wide-scale commercial application. Conventionally, rinse-added fabric softening compositions contain, as the active softening component, substantially water-insoluble cationic materials having two long alkyl chains. Typical of such materials are ditallow alkyl dimethyl ammonium chloride and imidazolinium compounds substituted with two stearyl or tallow alkyl groups. These materials are normally prepared in the form of a dispersion in water.
The use of various imidazoline derivatives as fabric conditioning agents is known. For example, British Patent Specification 1,565,808, published Apr. 23, 1980, discloses textile fabric softener compositions consisting of an aqueous dispersion of imidazoline ester derivatives. Similarly, methods for preparing various imidazoline derivatives are known in the art. See for example, U.S. Pat. No. 4,233,451, Pracht, issued Nov. 11, 1980, U.S. Pat. No. 4,189,593, Wechsler et al., issued Feb. 19, 1980, and Japanese Laid Open Publication 61-291571.
Various solutions to the problem of preparing concentrated fabric softening compositions suitable for consumer use have been addressed in the art. See, for example, U.S. Pat. Nos.: 4,426,299, issued Jan. 17, 1984, and 4,401,578, issued Aug. 30, 1983, Verbruggen, which relate to paraffin, fatty acids and ester extenders in softener concentrates as viscosity control agents.
European Pat. No. 0,018,039, Clint et al., issued Mar. 7, 1984, relates to hydrocarbons plus soluble cationic or nonionic surfactants in softener concentrates to improve viscosity and stability characteristics.
U.S. Pat. No. 4,454,049, MacGilp et al., issued Jun. 12, 1984, discloses concentrated liquid textile treatment compositions in the form of isotropic solutions comprising water-insoluble di-C.sub.16 -C.sub.24 optionally hydroxy-substituted alkyl, alkaryl or alkenyl cationic fabric softeners, at least about 70% of the fabric softener consisting of one or more components together having a melting completion temperature of less than about 20.degree. C., a water-insoluble nonionic extender, especially C.sub.10 -C.sub.40 hydrocarbons or esters of mono- or polyhydric alcohols with C.sub.8 -C.sub.24 fatty acids, and a water-miscible organic solvent. The concentrates have improved formulation stability and dispersibility, combined with excellent fabric softening characteristics.
U.S. Pat. No. 4,439,330, Ooms, issued Hat. 27, 1984, teaches concentrated fabric softeners comprising ethoxylated amines.
U.S. Pat. No. 4,476,031, Ooms, issued Oct. 9, 1984, teaches ethoxylated amines or protonated derivatives thereof, in combination with ammonium, imidazolinium, and like materials.
The use of alkoxylated amines, as a class, in softener compositions is known (see, for example, German Patent Applications 2,829,022, Jakobi and Schmadel, published Jan. 10, 1980, and 1,619,043, Hueller et al., published Oct. 30, 1969, and U.S. Pat. Nos.: 4,076,632, Davis, issued Feb. 28, 1978, and 4,157,307, Jaeger et al., issued June 5, 1979).
It is generally known (for example, in U.S. Pat. No. 3,681,241, Rudy, issued Aug. 1, 1972) that the presence of ionizable salts in softener compositions does help reduce viscosity.
Copending U.S. Pat. Application Set. No. 07/693,493, Vogel, Watson, Wahl and Benvegnu, filed Apr. 30, 1991, teaches softening compositions containing imidazoline mixtures with ethoxylated materials as scum dispersants.
The prior art generally discloses that amines, and especially imidazolines, used in fabric softening compositions preferably should be protonated with hydrochloric acid (HCl), orthophosphoric acid (OPA) C.sub.1 to C.sub.5 carboxylic acids or other similar acids for use in fabric softening compositions. (See e.g., U.S. Pat. No. 4,965,100, Leigh et al., issued Oct. 23, 1990; U.S. Pat. No. 4,954,270, Butterworth et al., issued Sept. 4, 1990; U.S. Pat. No. 4,360,437, Wolfes, issued Nov. 23, 1982; U.S. Pat. No. 4,233,164, Davis, issued Nov. 11, 1980; and U.S. Pat. No. 4,876,355, Hughes et al., issued Oct. 24, 1989.)
U.S. Pat. No. 4,808,321, Walley, issued Feb. 28, 1989, teaches fabric softening compositions comprising a quaternary ammonium compound at pH of from 2 to 5, which are free of unprotonated amines or where the amines are protonated with strong acids to enhance hydrolytic stability of the composition.
U.S. Pat. No. 4,789,491, Chang et al., issued Dec. 6, 1988, teaches a method of making stable compositions with quaternized di-esters or di-isopropanol amines using narrow pH and temperature ranges.
U.S. Pat. No. 5,061,385, Duffin, issued Oct. 29, 1991, discloses a rinse cycle fabric-treatment composition containing imidazolines. The composition is prepared by adding water to a molten premix of active materials to form a water-in-oil emulsion. Upon further addition of water this phase is reversed to a finely dispersed oil-in-water emulsion. The pH of the composition is between 2 and 7, preferably from 3 to 4.5.
U.S. Pat. No. 4,933,096, Demeyere et al., issued Jun. 12, 1990, discloses a textile treatment composition comprising 1-40% imidazoline and a dispersing acid, having good hydrolytic stability and low viscosity. In a one-step process the molten imidazoline is added to the acid/water seat under high shear mixing. The pH of this dispersion is from 2.5 to 6, preferably from 3 to 5.
U.S. Pat. No. 4,724,089, Konig et al., issued Feb. 9, 1988, P&G, teaches a rinse-added fabric softener composition comprising imidazoline and a Bronstedt acid as a dispersion aid. In a one-step process molten imidazoline is added to an acid/water seat of sufficient acid concentration to keep the pH at 5 or below.
U.S. Pat. No. 4,806,255, Konig et al., issued Feb. 21, 1989, teaches rinse-added fabric softener compositions comprising an amine, including imidazoline, a quaternary ammonium softening agent, with an optional Bronstedt acid as a dispersing aid.
U.S. Pat. No. 4,661,267, Dekker et al., issued Apr. 28, 1987, discloses a rinse-added fabric softener composition comprising a cyclic amine such as imidazoline, and a soil release polymer, with a pH range of 2 to 6.5. A Bronstedt acid is optional.
European Pat. Appln. No. 409,503, Tandela, published Jan. 23, 1991, describes fabric softening compositions comprising an amine softener, including imidazoline, a fatty acid, and a buffer acid.
European Pat. Appln. No. 404,471, Machin et al., published Dec. 27, 1990, discloses concentrated fabric softening compositions with at least 20% by weight of the fabric softener active, including imidazoline, and at least 5% by weight of an organic acid preferably between 15-30% by weight of the composition with improved stability and appearance. The composition's pH is between 2 and 5.
E.P.A. No. 443,313, published Aug. 28, 1991, teaches the addition of a neutralizing acid to an esteramine material for improved dispersibility in rinse water and softening benefits.
It is highly desirable to prepare physically-acceptable textile treatment compositions containing biodegradable, water-insoluble, softener materials that exhibit excellent softening performance. However, materials which are biodegradable are often difficult to formulate as stable liquid compositions, especially at high concentrations. Various solutions in the art have not been entirely satisfactory.
It is a preferred object of this invention to provide an effective, storage-stable, preferably biodegradable, liquid fabric softening composition. It is a further object to provide such materials in the form of liquid concentrates.
All of the above patents, patent applications, and publications are incorporated herein by reference.